Tungsten heavy alloy sheet can be produced by rolling sintered billets of the alloy. Because the rolling requires numerous anneals, it is desirable that the starting billet be no more than about twice the final thickness. One method to produce these billets is by isostatically pressing the powder alloy blends and sintering them to full density. With thin billets, it is difficult to to get a uniform fill of the mold so the resulting billets are not uniform in thickness. There is also a problem with breakage with the thin billets. By this method it is not possible to produce billets with a surface area to thickness ratio much over 600 or thicknesses less than about 0.5". A similar method is to press large billets and cut the green billet into thin slabs. While this produces billets of uniform thickness, it has the size limitations of the previous method and there is the added expense of cutting.
Several other methods of preparing rollling slabs involve preparing a thick slurry of the powder blend with binders and other agents and then preparing the sheet from the slurry by extruding, tape casting, or pouring and leveling on a table. Once the solvent is removed, the sheet can be handled and cut. These methods can produce thin sheets but thicker sheets are difficult or impossible to form. A big disadvantage of these processes is that binder addition and binder removal steps must be inserted into the process. Also it is difficult to obtain optimum mechanical properties in tungsten heavy alloys that have been prepared with organic binders used somewhere in the process. This is due to presence of carbon in the organics.